Bone defects that may result from fractures, accidents, cancer, or other diseases can pose a serious risk of loss of bone function, and thereby impair the quality of life. Tissue grafting methods, etc. are currently used for the treatment of bone diseases, but these methods still have limitations such as donor site morbidity and graft rejection.
Meanwhile, due to the flexibility in selecting and mimicking the local structural features of proteins, peptides can functionally serve as valid alternatives to entire proteins. Peptides have advantages in that they have a low molecular weight, synthetic versatility, and economical production. The use of peptides in regenerative medicine has advantages over the use of entire proteins in terms of lowering immunogenicity, susceptibility to protein degradation, tumor-related side effects, etc., and is superior in terms of drug targeting, drug potency, stability, and bioavailability compared to those of other protein-based biological therapeutics. Until now, many peptides have been used for local applications to repair bone defects in clinical settings; however, only very few peptides were shown to have the ability to form bone themselves, and these peptides also have many disadvantages in that the use thereof for therapeutics is associated with high cost, etc.
Meanwhile, bone mass and structure are maintained through a dynamic balance between bone resorption and formation. An imbalance caused by the increased activity and/or number of osteoclasts leads to bone destruction in pathological bone diseases, including osteoporosis, Paget's disease, rheumatoid arthritis, osteolytic metastases, etc. Therefore, much attention has been focused on the pharmacological control of osteoclasts for the treatment of osteoclast-related bone disorders including osteoporosis and arthritis.